(a) Field Of The Invention:
This invention relates to firearms of the break-open type, that is, firearms in which the action is opened by breaking the barrel assembly including the breech about a transverse hinge axis relative to a receiver attached to the butt and having a pair of longitudinal side walls accommodating the breech between them and pivotally connected with the breech by a hinge device. More particularly, the invention is concerned with the hinge device.
(b) Prior Art:
Different forms of hinge devices for break-open firearms are known in the art. The predominant form includes a pivot pin or trunnions defining the hinge axis and sometimes associated with lugs or other elements providing additional surfaces aiding in carrying the recoil forces. Even if such additional surfaces are present, the combined area of the surfaces carrying the recoil forces is relatively small with this form, which also requires a foregrip fitting to hold the hinge device together.
In view of the tendency to use more powerful cartridges, and the increased recoil forces resulting therefrom, a demand for sturdier hinge devices has developed.
Attempts have been made to provide sturdier hinge devices. SE-B-363 893 illustrates an example of an improved hinge device, which comprises semi-circular ridges on the receiver side walls slidably received in complementary grooves formed on the lateral faces of the breech. In a modification of this form, the ridges are formed on the lateral faces of the breech, while the grooves are formed on the inner sides of the receiver side walls.
While the above-mentioned form is advantageous in some respects, it is unsatisfactory is that it does not lend itself to economical production of the receiver in monoblock form and in that its ability to carry heavy recoil forces is insufficient. Moreover, it does not facilitate assembly and disassembly of the main parts of the firearm.